Covalent Associates, Inc.

Yair Ein-Eli

Richard Laura

Wilmont F Howard, Jr

Acyclic, asymmetric methyl alkyl carbonates, particularly for use with a carbonaceous, e.g., graphite, anode, in electrolytes suitable for portable power sources, are disclosed. Asymmetric alkyl carbonate solvents, having the general structural formula MeO--CO.sub.2 R, where R is larger than methyl, can be used as the only solvent in the non-aqueous electrolyte of a portable power source; no other solvent is necessary for superior performance in, e.g., high energy density lithium ion batteries or high power electrochemical capacitors. Furthermore, an asymmetric alkyl methyl carbonate can serve as the primary solvent for a non-aqueous electrolyte, i.e., the solvent providing the requisite properties, with the appropriate volume balance being made up with a combination of cyclic and acyclic carbonates or esters chosen for a particular application.

Asymmetric organic alkyl methyl carbonates for non-aqueous power sources

Acyclic, asymmetric ethyl alkyl carbonates, particularly for use with a carbonaceous, e.g., graphite, anode, in electrolytes suitable for portable power sources, are disclosed. Asymmetric alkyl carbonates having the general structural formula EtO--CO.sub.2 R, where R is larger than ethyl, and most preferably equal to butyl, iso-butyl or sec-butyl, are particularly useful in causing the freezing point of the electrolytes in which they are used to decrease dramatically, thus providing the key to low temperature, high cycle life and high capacity for portable power sources.

Asymmetric organic alkyl ethyl carbonates for non-aqueous power sources

A series of electroactive insertion compounds, LiM.sub.y.sup.II M.sub.z.sup.III Mn.sub.l.sup.III Mn.sub.q.sup.IV O.sub.4 (0&lt;y+z.ltoreq.0.5, y+z+l+q=2), where M=any transition metal or combination of metals, for application in non-aqueous batteries, capacitors, and superconducting materials, are disclosed. These newly synthesized compounds are unique in that they contain at least two mixed valence elements, thereby allowing the reversible intercalation of lithium cations at potentials near 4.7-5.1 V vs. lithium. Also disclosed are novel copper insertion compounds of the formula LiM.sub.y Cu.sub.0.5-y Mn.sub.1.5 O.sub.4 (0.ltoreq.y.ltoreq.0.49), where M=one or more metals or transition metals. Such materials have also been found to be remarkably stable at this voltage upon repeated cycling.

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Waltham, MA, United States of America

Yair Ein-Eli